The design of rigid fixed bridge is superior to free-end fixed bridge and be propitious to the the health of the reserved root by dispersing the stress of reserved root more effectively.

The design of rigidly fixed bridge was superior to free-end fixed bridge and single crown.

CONCLUSION: Residual root being used for fixed-bridge abutment tooth may reduce healthy tooth being used in abutment tooth, and it can enlarge indications of repairing fixed-bridge.